The present invention relates to a bulk polymerization process at elevated temperatures and pressures for the direct production of substantially amorphous polyalphaolefins using a high activity supported catalyst system and more particularly to a process for the production of an amorphous propylene homopolymer, amorphous copolymers of propylene and ethylene, or amorphous interpolymers of propylene, ethylene and another alpha-olefin having from 4 to 8 carbon atoms per molecule. The amorphous polymer is the only product of the process and after separation of unreacted monomers, deactivation of catalyst residues in the polymer and polymer stabilization against heat and oxidation, the final product is recovered from the process.
The amorphous polyalphaolefin leaves the polymerization reactor as a 30-60% solution in liquid propylene, usually at temperatures in the range of 130.degree. F. and 175.degree. F. and at pressures between about 400 psig and about 550 psig. In conventional slurry polymerization processes for the production of highly crystalline isotactic propylene polymer, the reactor effluent is merely passed to a vaporization zone, usually a cyclone-bag filter combination, maintained at relatively low pressure, in which zone separation or flashing of unreacted propylene monomer occurs overhead while solid and substantially dry and free flowing polymer in powder form is recovered from the bottoms of the vaporization zone. Such an arrangement is completely unsuitable in an amorphous polyalphaolefin process due to the physical characteristics of the polymer product, i.e. the high viscosity and "stickiness" which will prevent it from being recovered as a powder solid on a nonplugging filter.
In addition, due to the inherent lowering in temperature in a flashing operation at reduced pressure, the product stream removed from the reactor will freeze and plug the conduits leading to the vaporization zone.
It is therefore an object of the present invention to provide an improved process for the separation of the amorphous polyalphaolefin from unreacted monomer(s).
It is another object of the invention to provide a process for the recovery of amorphous polyalphaolefin product in fluid form.
Further objects of the invention will become apparent from the detailed description of the invention.